This application claims foreign priority under 35 U.S.C. §119 to Belgian Application BE2014/0511 filed Jul. 3, 2014 titled “PLUNGER SLOT COVER ASSEMBLY FOR AN AGRICULTURAL BALER” and having Ronald Biebuyck, Frederik Demon and Karel Naeyaert as the inventors. The full disclosure of BE2014/0511 is hereby incorporated herein by reference.
1. Field of the Invention
The present invention relates to agricultural balers, and, more particularly, to bale chambers within such balers.
2. Description of the Related Art
Agricultural harvesting machines, such as balers, are used to consolidate and package crop material so as to facilitate the storage and handling of the crop material for later use. In the case of hay, a mower-conditioner is typically used to cut and condition the crop material for windrow drying in the sun. In the case of straw, an agricultural combine discharges non-grain crop material from the rear of the combine defining the straw (such as wheat or oat straw) which is to be picked up by the baler. The cut crop material is typically raked and dried, and a baler, such as a large square baler or round baler, straddles the windrows and travels along the windrows to pick up the crop material and form it into bales.
On a large square baler, a pickup unit at the front of the baler gathers the cut and windrowed crop material from the ground. The pickup unit includes a pickup roll, and optionally may include other components such as side shields, stub augers, wind guard, etc.
A packer unit is used to move the crop material from the pickup unit to a duct or pre-compression chamber. The packer unit forms a wad of crop within the pre-compression chamber which is then transferred to a main bale chamber. (For purposes of discussion, the charge of crop material within the pre-compression chamber will be termed a “wad”, and the charge of crop material after being compressed within the main bale chamber will be termed a “flake”). Typically such a packer unit includes packer tines or forks to move the crop material from the pickup unit into the pre-compression chamber. Instead of a packer unit it is also known to use a rotor cutter unit which chops the crop material into smaller pieces.
A stuffer unit transfers the wad of crop material in charges from the pre-compression chamber to the main bale chamber. Typically such a stuffer unit includes snuffer forks which are used to move the wad of crop material from the pre-compression chamber to the main bale chamber, in sequence with the reciprocating action of a plunger within the main bale chamber.
In the main bale chamber, the plunger compresses the wad of crop material into flakes to form a bale and, at the same time, gradually advances the bale toward the outlet of the bale chamber. The plunger reciprocates, back and forth, toward and away from the discharge end of the baler. The plunger may include a number of rollers which extend laterally outward from the sides of the plunger. The rollers on each side of the plunger are received within a respective plunger slot formed in the side walls of the bale chamber, with the plunger slots guiding the plunger during the reciprocating movements.
When enough flakes have been added and the bale reaches a full (or other predetermined) size, a number of knotters are actuated which wrap and tie twine, cord or the like around the bale while it is still in the main bale chamber. The twine is cut and the formed baled is ejected out the back of the baler as a new bale is formed.
During the bale formation within the bale chamber, as described above, crop material can be forced through the plunger slots on opposite sides of the bale chamber. The crop material can accumulate outside of the bale chamber, such as in an area around the axle, or in an area between the twine box and the frame. It is thus necessary for the operator to periodically dismount from the traction unit and clean the crop from the baler. This takes time and effort on the part of the operator, reducing the baling efficiency of the baler.
German patent document DD 288 309 B5 discloses a baler with a plunger slot arrangement having a panel that carries an upper guide rail and lower guide rail. Plunger rollers run between the guide rails. The panel provides the structural framework for the plunger slot arrangement, and appears to be formed as an extrusion which is closed on the side opposite from the plunger. Since the panel provides the structural support for the plunger slot arrangement, and also appears to be formed as an extrusion, the outside closed wall apparently extends the full length of the plunger slot arrangement. Crop material would tend to accumulate within the plunger slot, which in turn could negatively affect the reciprocating movement of the plunger rollers within the plunger slot.
What is needed in the art is an agricultural baler which avoids problems of crop accumulation in the plunger slot and areas outside of the bale chamber.